Risk factors for horizontal transmission of hepatitis B virus in a rural district in Ghana.

Most hepatitis B virus (HBV) infections in sub-Saharan African infants and children are acquired through horizontal transmission, but the exact mechanisms of spread have not been documented. The authors conducted a study in rural Ghana which determined seroprevalence in a probability sample of 1,385 individuals of all ages, and evaluated risk factors for horizontal transmission of HBV in a subsample of 547 children aged 1-16 years who were not hepatitis B surface antigen (HBsAg) carriers. Most residents in this district live in compounds which typically contain 2-4 households each. Overall prevalence of HBV seropositives (any HBV marker) was 74.7% (95% confidence interval (CI) 72.5%-76.9%). Prevalence of HBsAg was 20.9% (95% CI 18.8%-23.1%). The data suggest a continuous nonuniform acquisition of HBV infection with advancing age predominantly through horizontal transmission in childhood, with the household, rather than the domestic compound, being the primary place for transmission. The behaviors most strongly associated with prevalence of HBV were sharing of bath towels (OR = 3.1, 95% CI 2.1-4.5), sharing of chewing gum or partially eaten candies (OR = 3.4, 95% CI 2.3-5.0), sharing of dental cleaning materials (OR = 2.5, 95% CI 1.3-4.6), and biting of fingernails in conjunction with scratching the backs of carriers (OR = 2.5, 95% CI 1.6-4.3).